How SARS-CoV-2 Delta Variant Was Curbed in Japan. Will Omicron Replace It?

Curbing the SARS-CoV-2 Delta variant in Japan has probably initiated extinction of the Delta variant and the pandemic. Whether Omicron will replace Delta has been unknown so far. In case of Spanish flu, mass mortality reached an end two years later, although up to 2% of the population died in some villages at the Spanish flu outbreak in Yakutia in 1925 [23]. If Omicron replaces Delta, COVID-19 may probably turn into a seasonal infection, provided that the majority of the world population gets vaccinated or get sick.

Seasonal Prevalence and Novel Multilocus Genotypes of Giardia duodenalis in Yaks (Bos grunniens) in Qinghai Province, Western China

Background: Giardia duodenalis is an important opportunistic zoonotic intestinal protozoon, which could parasitize yaks. However, a few studies have been conducted on the seasonal infection of G. duodenalis in yaks in China. Methods: Overall, 1,027 fecal samples were collected from yaks of two age groups in seven cities of Qinghai Province, China at four seasons between May 2016 and Sep 2017. The prevalence and assemblages were analyzed by nested PCR and multilocus sequence typing (MLST). Results: The overall prevalence of G. duodenalis was 2.04% (21/1027) based on triose phosphate isomease (tpi) locus. No significant differences in prevalence of the organism in yaks were found among different sampling areas. Additionally, same result was also presented in different seasons. However, there was statistically significant difference between young yaks within 6 months (8.33%, 4/48) and adult yaks over 6 months (1.73%, 17/979). The assemblage A recognized as a zoonotic assemblage (n=3) was found in yaks (>6 months) from Xining, while assemblage E (n=18) was detected from yaks in six cities. There were 5, 2 and 3 G. duodenalis subtypes detected positive at the tpi, the β-giardin (bg), and the glutamate dehydrogenase (gdh) loci, with 2, 2 and 3 novel subtypes, respectively. Three samples were successfully sequenced at all three loci, forming 1 assemblages A multilocus genotype (MLG) and 2 assemblages E MLGs, not reported. Conclusion: This study indicated a zoonotic potential of G. duodenalis in yaks from Qinghai Province and provides basic information about the epidemiology of G. duodenalis.

Viral Ecology and Natural Infection Dynamics of Kaeng Khoi Virus in Cave-Dwelling Wrinkle-Lipped Free-Tailed Bats (Chaerephon plicatus) in Thailand

Kaeng Khoi virus (KKV; Order: Bunyavirales), is an endemic viral infection of the wrinkle-lipped free-tailed bat (Chaerephon plicatus aka Tadarida plicata plicata). Little is known about the ecology and maintenance of KKV within the bat population, nor the infection dynamics and transmission among bats or between bats and other vertebrates. Therefore, KKV was studied in Kaeng Khoi cave, Saraburi province, Thailand, during 1973–1974 with the objectives to (1) characterize the seasonal infection rates of KKV in the context of the bat population ecology, and (2) describe the infection dynamics and viral shedding by naturally- and experimentally-infected bats. To this end, the free-tailed bat population was estimated by a series of timed photographs taken during the evening exodus. The case population of 900,000 adult bats doubled at the time of weaning of the young and returned to its previous level soon thereafter. The newborn bats had neutralizing antibodies to KKV that were likely to be maternal in origin. The KKV antibody prevalence in adult bats was high (69–91%) in March–May and low (29–40%) in August and September. Kaeng Khoi virus was isolated from 75% of dead and 50% of moribund bats, but was not found in nearly 400 apparently healthy bats. Virus was present in saliva, urine and blood of most of the naturally-moribund bats tested. Consistent with observations from naturally-infected bats, experimental infection of bats with KKV revealed significant liver pathology, also suggestive that this is not a benign infection. Kaeng Khoi virus is an endemic, year-round infection maintained by the annual recruitment of a large number of immunologically-naïve juvenile bats. Moreover, it produces an acute infection in the bat, either leading to death by hepatitis, or immunity.

Seasonal patterns of malaria, genital infection, nutritional and iron status in non-pregnant and pregnant adolescents in Burkina Faso: a secondary analysis of trial data

Background Adolescents are considered at high risk of developing iron deficiency. Studies in children indicate that the prevalence of iron deficiency increased with malaria transmission, suggesting malaria seasonally may drive iron deficiency. This paper examines monthly seasonal infection patterns of malaria, abnormal vaginal flora, chorioamnionitis, antibiotic and antimalarial prescriptions, in relation to changes in iron biomarkers and nutritional indices in adolescents living in a rural area of Burkina Faso, in order to assess the requirement for seasonal infection control and nutrition interventions. Methods Data collected between April 2011 and January 2014 were available for an observational seasonal analysis, comprising scheduled visits for 1949 non-pregnant adolescents (≤19 years), (315 of whom subsequently became pregnant), enrolled in a randomised trial of periconceptional iron supplementation. Data from trial arms were combined. Body Iron Stores (BIS) were calculated using an internal regression for ferritin to allow for inflammation. At recruitment 11% had low BIS (< 0 mg/kg). Continuous outcomes were fitted to a mixed-effects linear model with month, age and pregnancy status as fixed effect covariates and woman as a random effect. Dichotomous infection outcomes were fitted with analogous logistic regression models. Results Seasonal variation in malaria parasitaemia prevalence ranged between 18 and 70% in non-pregnant adolescents (P < 0.001), peaking at 81% in those who became pregnant. Seasonal variation occurred in antibiotic prescription rates (0.7–1.8 prescriptions/100 weekly visits, P < 0.001) and chorioamnionitis prevalence (range 15–68%, P = 0.026). Mucosal vaginal lactoferrin concentration was lower at the end of the wet season (range 2–22 μg/ml, P < 0.016), when chorioamnionitis was least frequent. BIS fluctuated annually by up to 53.2% per year around the mean BIS (5.1 mg/kg2, range 4.1–6.8 mg/kg), with low BIS (< 0 mg/kg) of 8.7% in the dry and 9.8% in the wet seasons (P = 0.36). Median serum transferrin receptor increased during the wet season (P < 0.001). Higher hepcidin concentration in the wet season corresponded with rising malaria prevalence and use of prescriptions, but with no change in BIS. Mean Body Mass Index and Mid-Upper-Arm-Circumference values peaked mid-dry season (both P < 0.001). Conclusions Our analysis supports preventive treatment of malaria among adolescents 15–19 years to decrease their disease burden, especially asymptomatic malaria. As BIS were adequate in most adolescents despite seasonal malaria, a requirement for programmatic iron supplementation was not substantiated.

Prevalence of Orthohantavirus-Reactive Antibodies in Humans and Peri-Domestic Rodents in Northern Ethiopia

In 2012, Tigray orthohantavirus was discovered in Ethiopia, but its seasonal infection in small mammals, and whether it poses a risk to humans was unknown. The occurrence of small mammals, rodents and shrews, in human inhabitations in northern Ethiopia is affected by season and presence of stone bunds. We sampled small mammals in two seasons from low- and high-density stone bund fields adjacent to houses and community-protected semi-natural habitats in Atsbi and Hagere Selam, where Tigray orthohantavirus was first discovered. We collected blood samples from both small mammals and residents using filter paper. The presence of orthohantavirus-reactive antibodies in blood was then analyzed using immunofluorescence assay (human samples) and enzyme linked immunosorbent assays (small mammal samples) with Puumala orthohantavirus as antigen. Viral RNA was detected by RT-PCR using small mammal blood samples. Total orthohantavirus prevalence (antibodies or virus RNA) in the small mammals was 3.37%. The positive animals were three Stenocephalemys albipes rats (prevalence in this species = 13.04%). The low prevalence made it impossible to determine whether season and stone bunds were associated with orthohantavirus prevalence in the small mammals. In humans, we report the first detection of orthohantavirus-reactive IgG antibodies in Ethiopia (seroprevalence = 5.26%). S. albipes lives in close proximity to humans, likely increasing the risk of zoonotic transmission.

Nosema ceranae - a new threat to honey bees (Apis mellifera)?

Back in 1900 already, the Microsporidium Nosema apis was described inApis mellifera. Thereby the Nosemosis remains without symptoms in the beehive to a certain degree. Studies indicate that infected bees have a shortened lifespan, due to a series of changes in physiological parameters. The consequence of these changes are diarrheal symptoms and the spread of infectious spores in thehive. There is also a seasonal infection course observed, which has its peak in spring time (April, May). Colloquially, the Nosemosis is therefore also known as spring shrinking craze. More recently, a new Nosema species in the European honey bee has been described, where a host-switch from the Asian honey bee A. cerana to A. mellifera has occurred. N. ceranae is blamed for colony losses in the south of Spain, many general colony losses during wintertime in Europe and has also a contribution to the Colony Collapse Disorder (CCD) in the U.S. It seems likely that the original Nosema species (N. apis) is displaced more and more by N. ceranae for unknown reasons. Within the EU project „BEE DOC“, monitoring studies on colonies in southern Germany, Switzerland, southern France, Sweden and Finland were performed. Although the high prevalence of N. ceranae could be confirmed, no increased colony mortality due to Nosemosis was recorded. This was also observed by other colleagues and thus the „new threat“ is open to debate.

Influence of EPs 7630 on Antipyretic Comedication and Recovery from Acute Tonsillopharyngitis in Children: A Meta-analysis of Randomized, Placebo-Controlled, Clinical Trials

Objective Acute tonsillopharyngitis (ATP) is a common, seasonal infection of predominantly viral origin. Management is aimed at shortening the course of the disease and restoring the comfort of the patient. We performed a meta-analysis to investigate whether treatment with the Pelargonium sidoides extract EPs 7630 reduces the use of antipyretic comedication (i.e., acetaminophen) in children suffering from ATP. Methods Studies were identified from clinical trial registries and medical literature. Randomized, placebo-controlled, clinical trials investigating EPs 7630 in children with ATP and reporting the coadministration of paracetamol were eligible. Based on the raw data of eligible trials, we analyzed cumulative paracetamol use, as well as the ability to attend school at the end of treatment. Three trials including a total of 345 children aged 6 to 10 years and suffering from non-β-hemolytic streptococcal ATP were identified and eligible. Children were administered EPs 7630 or placebo for 6 days. Results Compared with placebo, EPs 7630 reduced the cumulative paracetamol dose by an average of 449 mg (95% confidence interval [CI]: 252–646 mg; p < 0.001). A total of 19.1% (EPs 7630) and 71.5% (placebo) of children were still unable to attend school at the end of the treatment (risk ratio = 0.28; 95% CI: 0.16–0.48; p < 0.001). Conclusion Our meta-analysis demonstrates that EPs 7630 reduced the use of antipyretic comedication and accelerated recovery.

Waning of Measured Influenza Vaccine Effectiveness Over Time: The Potential Contribution of Leaky Vaccine Effect

Background Several observational studies have shown decreases in measured influenza vaccine effectiveness (mVE) during influenza seasons. One study found decreases of 6–11%/month during the 2011–2012 to 2014–2015 seasons. These findings could indicate waning immunity but could also occur if vaccine effectiveness is stable and vaccine provides partial protection in all vaccinees (“leaky”) rather than complete protection in a subset of vaccinees. Since it is unknown whether influenza vaccine is leaky, we simulated the 2011–2012 to 2014–2015 influenza seasons to estimate the potential contribution of leaky vaccine effect to the observed decline in mVE. Methods We used available data to estimate daily numbers of vaccinations and infections with A/H1N1, A/H3N2, and B viruses. We assumed that vaccine effect was leaky, calculated mVE as 1 minus the Mantel-Haenszel relative risk of vaccine on incident cases, and determined the mean mVE change per 30 days since vaccination. Because change in mVE was highly dependent on infection rates, we performed simulations using low (15%) and high (31%) total (including symptomatic and asymptomatic) seasonal infection rates. Results For the low infection rate, decreases (absolute) in mVE per 30 days after vaccination were 2% for A/H1N1 and 1% for A/H3N2and B viruses. For the high infection rate, decreases were 5% for A/H1N1, 4% for A/H3, and 3% for B viruses. Conclusions The leaky vaccine bias could account for some, but probably not all, of the observed intraseasonal decreases in mVE. These results underscore the need for strategies to deal with intraseasonal vaccine effectiveness decline.